We would like to propose a new building for embassy in Tokyo designed as Tent on the Water.The new embassy building is to be a structure covered by light and modern tent. Just as those nomads who traveled on the sands at one time in the past could enjoy cool at camping tents, this modern and contemporary tent provides comfortable inner environment passively to the people by controlling outer environment an origin of the mane of the State, which means "Castle built adjacent to the water source" the water is prepared at the foot of the tent. The water welcomes visitors with solemnity, and also gives people inside there the sense of healings.People always can feel water with their eyes and ears through the void.The silhouette of the tent with top at the southern corner looks symbolic and new embassy building will become a landmark representing a dignity.